This invention relates to a photosensor. More particularly, it relates to a thin-film photosensor, which can be used in, for example, the photosensor array of a facsimile transmitter or the like as a photoelectric converter for plane picture information.
Heretofore, a linear array of silicon photodiodes has been generally employed as a photoelectric conversion sensor for a facsimile transmitter. Since, however, the size of a silicon single crystal being producible is subject to limitation, the linear array of silicon photodiodes is difficult to be elongated.
On the other hand, a thin film photosensor array employing a CdSe film, an Se-As-Te amorphous thin film or the like as a photoconductor can be produced by the vacuum evaporation and can therefore be made elongated. A transparent electrode used in such sensor, however, has had the disadvantages that the resistivity thereof is high as compared with that of a metal, so the wiring resistance becomes high when the transparent electrode is wired as a minute electrode, and that when the part of the electrode other than a window for the incidence of a light signal is left transparent, unnecessary light signals are mixed to degrade the resolution of an image picked up. A further disadvantage is that in case of electrically connecting the transparent electrode and a wiring conductor, two photoetching steps of high precision are required for individually forming them.